Regensburg 2010 – scientific programme

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DS: Fachverband Dünne Schichten

DS 43: Biomolecular and Functional Organic Layers II (Focused Session)

DS 43.7: Talk

Friday, March 26, 2010, 13:15–13:30, H2

Structural Characterization of Self-assembled Monolayers of Pyridine-terminated Thiolates on Gold — •Jinxuan Liu¹, Björn Schüpbach², Asif Bashir³, Osama Shekhah¹, Alexei Nefedov¹, Martin Kind¹, Andreas Terfort², and Christof Wöll⁴ — ¹Lehrstuhl für Physikalische Chemie I, Ruhr-Universität Bochum, 44780 Bochum, Germany — ²Institut für Anorganische und Analytische Chemie, Goethe-Universität Frankfurt am Main, 60325 Frankfurt, Germany — ³Interface Chemistry and Surface Engineering, Max-Planck-Institut für Eisenforschung, 40237 Düsseldorf, Germany — ⁴Institute of Functional Interfaces, Karlsruhe Institute of Technology (KIT), 76021 Karlsruhe, Germany

Self-assembled monolayers (SAMs) on Au from a homologous series of four pyridine-terminated organo thiols have been investigated using a variety of surface-analytical techniques (IR, XPS, NEXAFS, STM) and DFT calculations. For all pyridine-terminated thiols the immersion of Au-substrates in the corresponding ethanolic solutions was found to result in the formation of highly ordered and densely packed SAMs. For an even number of the methylene spacers between the SH group and the aromatic moieties the SAM unit-cell is rather large, 5√3× 3, whereas in case of an odd number of methylene units a smaller unit cell is adopted, 2√3×√3 R30^∘. The tilt-angle of the molecules amounts to 15^∘. In contrast to expectation, the pyridine-terminated organic surfaces exposed by the corresponding SAMs showed a surprisingly strong resistance with regard to protonation.